<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <script src="../../../assets/js/vue-2.5.6.js"></script>
    <title>Watch option</title>
</head>

<body>
    <h1>Watch option</h1>
    <hr>
    <div id="app">
        <p>今日温度：{{temperature}}°C</p>
        <p>穿衣建议:{{this.suggestion}}</p>
        <p>
            <button @click="add">添加温度</button>
            <button @click="reduce">减少温度</button>

        </p>
    </div>

    <script type="text/javascript">
        var suggestion = ['T恤短袖', '夹克长裙', '棉衣羽绒服'];
        var app = new Vue({
            el: '#app',
            data: {
                temperature: 14,
                suggestion: '夹克长裙'
            },
            methods: {
                add: function() {
                    this.temperature += 5;
                },
                reduce: function() {
                    this.temperature -= 5;
                }
            },
            // watch:{
            //     temperature:function(newVal,oldVal){
            //         if(newVal>=26){
            //             this.suggestion=suggestion[0];
            //         }else if(newVal<26 && newVal >=0)
            //         {
            //             this.suggestion=suggestion[1];
            //         }else{
            //             this.suggestion=suggestion[2];
            //         }
            //     }
            // }
        })
        app.$watch('temperature', function(newVal, oldVal) {
            if (newVal >= 26) {
                this.suggestion = suggestion[0];
            } else if (newVal < 26 && newVal >= 0) {
                this.suggestion = suggestion[1];
            } else {
                this.suggestion = suggestion[2];
            }
        })
    </script>
</body>

</html>